With the beginning of World War I, however, Mussolini's political views appear to have undergone a sea-change: he declared his support for the nationalist cause, and joined the interventionistmovement. Opposed to participation in the war, the Socialist Party saw no recourse but to expel him from their ranks. Cut adrift, Mussolini founded a new newspaper, the Popolo d'Italia. The new daily advocated Italian participation in the war on the Allied side. As a result of this, it received financial support from the French, as a propaganda measure.

In 1915, Mussolini enlisted in the army, and achieved the rank of corporal. He was to use this "military career", such as it was, to great effect in his later life.

After the end of the war, Mussolini gathered to himself a crowd of disaffected war veterans and other dissatisfied Italians, and organised them into the Fasci di combattimento, nationalist gangs dressed in black shirts (copying the style adopted by D'Annunzio's followers). The Fasci pursued a confrontational, violent policy, clashing repeatedly with Communists and Socialists. Their watchword was a call for the restoration of order by force. Strikes, violence and social unrest contributed to an overall atmosphere of national breakdown.

As the dictator of Italy, Mussolini (called il Duce, "the Leader", by his followers) deliberately adopted a Roman imperial style, surrounding himself with as many references to the grandeur of ancient Rome as possible. With the construction of monumental buildings, and with an extensive effort in archaeological restoration of ancient Roman edifices, Mussolini's Italy was an Italy that dwelt on past greatness, and had expectations of future greatness.

With the growth of GermanNational Socialism in the 1930s, it was perhaps inevitable that Adolf Hitler and Benito Mussolini would have to reach an understanding. Even so, Mussolini was initially standoffish. Mussolini, though in many ways a thug, was essentially a sane man, and Hitler was not. Hitler was not to Mussolini's liking. However the international community's diplomatic coolness towards Italy following the war in Ethiopia in 1935 made Hitler more attractive as an ally. A three-part mutual understanding between Hitler, Mussolini and Francisco Franco of Spain led to Italian and German aid to the Spanish Fascists in the Spanish Civil War, from 1936. In 1938, Mussolini aided Hitler in the Anschluss, the annexation of Austria by Germany, and in 1939, Germany and Italy entered into a formal alliance.

Mussolini was never violently opposed to the Jews, but under German pressure, he found himself forced to institute a series of anti-Jewish measures. These did not enjoy great support by the Italian public, however.

With the outbreak of World War II, Mussolini chose to play a waiting game. Italy did not enter the war on the German side until June, 1940, shortly before the fall of France. The war did not go well for Italy. Losses in Greece and Africa, and the prospect of invasion of Italy by the Allies, led to unrest in the Fascist party. In July, 1943, Mussolini was deposed and imprisoned.

Immediately after Mussolini's death in 1945 by firing squad his body was taken from the execution site to a square in Milan where it was to be displayed. This was the time that angry mobs of former dissidents under the Fascist Regime of Mussolini took it upon themselves to express their anger upon the body of Mussolini itself.

The country was bankrupt, there were many refugees and homeless and all due to Mussolini's policies and domestic strong arm tactics. This was fuel to their rage. His and the body of his mistress were dragged from the firing squad through the streets where people spat, struck, kicked and threw rocks at the corpses. Many went so far as to kick and stomp the head and face specifically of Il Duce.

Finally, upon arrival in the square, strings from a piano (i.e. wires) were procured and used to hang the bodies by their feet. The violence perpetrated on the corpses was such that they were unrecognizable; a violent and graphic testament to the passion of the Italian people of the time. Furthurmore, this possibly served as a warning to would-be dictators waiting in the wings; the Italian people were through with Fascism or totalitarianism of any type. It seems to have been effective since Italy has remained democratic ever since.

Afterwards, three autopsies were performed. The body was stolen from its original grave by still sympathetic Fascists and not returned to the widow until eleven years later.